• win — The identifier of the window to be removed.

• dlgitem — The value of the control's id attribute.

• event — The type of event. It can be one of the following strings:

◦ WINDOW_LOAD — When the window is first loaded.

◦ WINDOW_CLOSED — When the window is closed.

◦ WINDOW_FOCUSED — When the window is activated.

◦ WINDOW_UNFOCUSED — When the window is deactivated.

◦ WINDOW_DOCK_CHANGED — When the docking state of the dialog is changed. For this event only, data holds the old docking state. For example, "top", "right", "none", and so on.

• data — User data value that is passed to the callback.

• appdata — Specifies a value for later reference.